Exam 15: Genetics of Bacteria and Bacteriophages

Minimal media is

In general,transformation of most genes occurs at a frequency of one in every ________ cells.

When Lederberg and Tatum performed their experiments on gene transfer in bacteria that lead to our understanding of conjugation,what were their controls?

How does a bacteriophage become a transducing phage?

For a P1 transduction experiment,an E.coli donor strain with the genotype arg⁺,ser⁺,amp^R and a recipient strain with the genotype arg^-,ser^-,amp^S were used.The following results were obtained for each marker: Of the transductants selected for arginine,5% are ser⁺ and 30% are amp^R. Of the transductants selected for serine,3% are arg⁺ and 0% are amp^R. What is the correct order and relative distance of these three genes on the E.coli chromosome?

mtl,polA,and xyl are bacterial genes that can be transmitted using an Hfr strain.An interrupted mating experiment resulted in xyl exconjugants appearing at 7 minutes and reaching maximum level by 30 minutes.The mtl gene function exconjugants appeared at 11 minutes and leveled off at 80% maximum by about 33 minutes,while polA did not appear until 24 minutes into the experiment and then only slowly rose to about 30%.Which of the following shows the gene order with the insertion site (arrow)location correctly?

A bacterial broth culture is diluted by a factor of 100,000,and 0.1 mL of the dilution is spread over the surface of an agar plate.The next day,123 colonies are observed on the plate.What was the concentration of bacteria in the broth?

To grow on artificial medium,prototrophic bacteria require

In bacteriophage T4,all rIIA mutants are found to complement all rIIB mutants.However,rIIA mutants fail to complement other rIIA mutants,and rIIB mutants fail to complement other rIIB mutants.Furthermore,mutants with deletions that span both rIIA and rIIB complementation groups do not complement either A or B mutants.What do these data mean,and what do the complementation groups represent?

How could you use T2 bacteriophage plaque phenotypes to determine the genetic distance between two genes,h and r,that affect plaque appearance in the phage DNA?

Genetic exchange in bacteria by transduction requires cell-to-cell contact.

In the lysogenic bacteriophage life cycle,the λ chromosome

How would you design an experiment to test whether a transduction event occurred between two different bacterial strains?

What is the difference between generalized and specialized transduction? Give an example of specialized transduction.

The viral chromosome of a bacteriophage can never integrate into the host bacterium's chromosome.

Genetic mapping experiments performed by Seymour Benzer on rII mutants in the T4 phage showed that the gene is indivisible by the process of mutation and recombination.

A complete bacterial medium contains only the nutrients required for the growth of wild-type cells.

In genetic exchange by conjugation,a single Hfr strain will transfer the entire bacterial chromosome to the recipient,allowing mapping in minutes from the first gene entering to the last one before the other half of the inserted F factor.

Explain how an F' × F^- conjugation can produce a partially diploid bacterial cell.

To enhance the efficiency of transformation,bacterial cells can be induced to take up DNA by a strong electrical field.